Interoperability gateway for land mobile radio system

ABSTRACT

Disclosed is an interoperability gateway system that provides backup connection between a dispatch center and a Land Mobile Radio (LMR) system in the event the dispatch center is disconnected from the LMR system. In general, this may be accomplished by providing an RF link between the disconnected site and the interoperability gateway via a controller, or interoperability site network interface (ISNI), that is activated when the dispatch center is disconnected from the LMR system. The interoperability gateway provides the backup connection by allocating a control station for each channel available at the disconnected LMR system. When compared to conventional dispatch console backup schemes, the disclosed interoperability gateway system greatly reduces the equipment needed to provide dispatch console backup, thereby decreasing equipment and operation costs, and simplifying operation by providing a solution that is virtually transparent to the dispatcher.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims the benefit of U.S. patent application Ser. No. 15/786,476, entitled “Interoperability Gateway for Land Mobile Radio System,” filed Oct. 17, 2017, and naming Arindam Roy, Brandon Hudson Yarbrough, Jon Bartosch, and Steven Newman as inventors, which is a continuation of and claims the benefit of, U.S. Pat. No. 9,800,460, entitled “Interoperability Gateway for Land Mobile Radio System,” filed Jul. 31, 2015, and naming Arindam Roy, Brandon Hudson Yarbrough, Jon Bartosch, and Steven Newman as inventors, which is a non-provisional of and claims priority to U.S. Provisional Patent Application Ser. No. 62/032,376, entitled “Interoperability Gateway for Land Mobile Radio System,” filed Aug. 1, 2014, and naming Arindam Roy, Brandon Hudson Yarbrough, Jon Bartosch, and Steven Newman as inventors, the disclosures of which are incorporated herein by reference in their entirety.

FIELD

The present disclosure relates generally to Land Mobile Radio (LMR) communication systems. More specifically, but not by way of limitation, the present disclosure relates to a system for providing backup connection between a dispatch center and an LMR system in the event the dispatch center is disconnected from the LMR system.

BACKGROUND

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

Land Mobile Radio (LMR) systems are deployed by organizations requiring instant communication between geographically dispersed and mobile personnel. Current LMR systems can be configured to provide for radio communications between one or more sites and subscriber radio units in the field. A subscriber radio unit (hereinafter “radio”) may be a mobile unit or a portable unit. LMR systems can be as simple as two radio units communicating between themselves over preset channels, or they can be complex systems that include hundreds of radio units and multiple sites. Typical users of LMR systems include police departments, fire departments, medical personnel, security personnel, EMS, and the military.

LMR systems are usually connected to a dispatch center, which provides functionality for call routing and interoperability between various systems and devices. FIG. 1 illustrates an example embodiment of a dispatch center 110 deployed in an LMR system, wherein the dispatch center 110 hosts multiple consoles 115, a gateway 120, and control station 125. The dispatch center 110 maintains a wired connection 130 to an LMR system 100 comprising one or more LMR sites 135. Radios 140 communicate at the LMR site 135 over radio frequency (RF) connections 145, and calls are passed to the consoles 115 over the wired connection 130 between the LMR system 100 and dispatch center 110.

If the wired connection 130 is lost, the radio calls are not received by the consoles 115. Therefore, as backup, a gateway 120 is deployed in the dispatch center 110, wherein the gateway 120 is connected to a radio or control station 125 that is capable of communicating on the system 100 with a particular TalkGroup. A dispatcher, upon recognizing being disconnected from the system 100, instructs the control station 125 to operate on a particular TalkGroup. The control station 125, through the gateway 120, provides the dispatcher a wireless connection 150 to users of the particular TalkGroup. As such, the dispatcher has access to the LMR system 100 via a wireless connection 150 for only the particular TalkGroup provided by the gateway 120 and control station 125.

The gateway 120 and control station 125 are capable of providing a dispatcher access to only one TalkGroup. Thus, to provide access to the LMR system 100 for each TalkGroup supported by the system 100, an additional gateway 120 and control station 125 is needed to support each additional TalkGroup, thereby substantially increasing operation and equipment costs. For example, to support each TalkGroup for a system having twelve channels and 100 TalkGroups, the dispatch center would require deployment of 100 gateways and 100 control stations to provide full backup console functionality. Furthermore, each gateway/control station combination is configured as a separate TalkGroup on the dispatch console 115 to distinguish them from active TalkGroups maintained between the consoles 115 and system 100, thereby increasing complexity and occupying valuable screen space on the dispatcher's console 115.

SUMMARY

The present disclosure provides an interoperability gateway system and method for providing seamless backup connection between a dispatch center and an LMR system.

In one embodiment the present disclosure provides a gateway system for providing backup connection between a dispatch center and a Land Mobile Radio (LMR) system when the dispatch center is disconnected from the LMR system, the gateway system comprising: a controller configured to detect the disconnection between the dispatch center and the LMR system; a plurality of control stations coupled to the controller via an IP network, wherein each of the control stations are configured to establish a communication link between the dispatch center and the disconnected LMR system; wherein the controller is further configured to, in response to detecting the disconnection, allocate a first one of the plurality of control stations as a control channel for the disconnected LMR system, and allocate a second one of the plurality of control stations as a voice channel for communicating with the disconnected LMR system over the voice channel.

In another embodiment, the present disclosure provides a system for providing backup connection between a dispatch center and a Land Mobile Radio (LMR) system when the dispatch center is disconnected from the LMR system, the system comprising: a controller configured to detect the disconnection between the dispatch center and the LMR system; two or more control stations coupled to the controller via an IP network, wherein at least one of the two or more control stations is configured to establish a communication link between the dispatch center and the disconnected LMR system; wherein the controller is further configured to, in response to detecting the disconnection, allocate a first one of the two or more control stations as a control channel for the disconnected LMR system, and allocate a second one of the two or more control stations as a voice channel for communicating with the disconnected LMR system over the voice channel.

In yet another embodiment, the present disclosure provides a method for providing backup connection between a dispatch center and a Land Mobile Radio (LMR) system when the dispatch center is disconnected from the LMR system, the method comprising: detecting, via a controller, the disconnection between the dispatch center and the LMR system; establishing, via at least one of a plurality of control stations, a communication link between the dispatch center and the disconnected LMR system; and allocating, via the controller in response to detecting the disconnection, a first one of the plurality of control stations as a control channel for the disconnected LMR system, and a second one of the plurality of control stations as a voice channel for communicating with the disconnected LMR system over the voice channel.

Further embodiments and apparatuses, including other areas of applicability, will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure in any manner.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of various embodiments of the present disclosure and the advantages thereof, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts, and in which:

FIG. 1 illustrates an example embodiment of a dispatch center deployed in an LMR system;

FIG. 2 illustrates an example embodiment wherein the disclosed interoperability gateway is hosted at various dispatch centers connected via an IP network to an LMR system having one or more LMR sites;

FIG. 3 illustrates the example embodiment shown in FIG. 2, wherein one of the dispatch centers is disconnected from the LMR system;

FIG. 4 illustrates an example embodiment wherein the interoperability gateway is implemented in the backup console mode of operation to provide a connection between a dispatch center and an LMR system when the dispatch center loses its wired connection to the LMR system;

FIG. 5 illustrates an example embodiment wherein the interoperability gateway is implemented to provide interoperability between a trunking LMR system and a P25 console system;

FIG. 6 illustrates an example embodiment wherein the interoperability gateway is implemented to provide interoperability between a trunking LMR system and a P25 LMR system; and

FIG. 7 illustrates an example flow diagram of a method for providing backup connection between a dispatch center and a Land Mobile Radio (LMR) system when the dispatch center is disconnected from the LMR system.

DETAILED DESCRIPTION

In the following detailed description and the attached drawings, numerous specific details are set forth to provide a thorough understanding of the present disclosure. However, those skilled in the art will appreciate that the present disclosure may be practiced, in some instances, without such specific details. In other instances, well-known elements have been illustrated in schematic or block diagram form in order not to obscure the present disclosure in unnecessary detail. Additionally, for the most part, specific details, and the like, have been omitted inasmuch as such details are not considered necessary to obtain a complete understanding of the present disclosure, and are considered to be within the understanding of persons of ordinary skill in the relevant art.

It is further noted that, unless indicated otherwise, all functions described herein may be performed in hardware or as software instructions for enabling a computer, radio or other device to perform predetermined operations, where the software instructions are embodied on a computer readable storage medium, such as RAM, a hard drive, flash memory or other type of computer readable storage medium known to a person of ordinary skill in the art. In certain embodiments, the predetermined operations of the computer, radio or other device are performed by a processor such as a computer or an electronic data processor in accordance with code such as computer program code, software, firmware, and, in some embodiments, integrated circuitry that is coded to perform such functions. Furthermore, it should be understood that various operations described herein as being performed by a user may be operations manually performed by the user, or may be automated processes performed either with or without instruction provided by the user.

The present disclosure provides an interoperability gateway system and method capable of providing functionality for communicating between LMR systems. For example, the interoperability gateway may convert a voice type or call type from one LMR system to a voice type or call type suitable for another LMR system, wherein the LMR systems may be of same types or different types. Examples of such LMR system types may include E F Johnson's ATLAS® P25 system, other P25 systems, conventional LMR systems, trunking LMR systems, hybrid LMR systems, wide area systems such as simulcast LMR systems and multicast LMR systems, and other LMR systems.

In some embodiments, the interoperability gateway system and method provides backup dispatch console functionality between a dispatch center and an LMR system in the event the dispatch center is disconnected from the LMR system. In general, this may be accomplished by providing an RF link between the disconnected site and the interoperability gateway via a controller, or interoperability site network interface (ISNI), that is activated when the dispatch center is disconnected from the LMR system. As discussed in greater detail below, the interoperability gateway provides the backup connection by allocating a control station for each channel (rather than for each TalkGroup) available at the disconnected LMR system. When compared to conventional dispatch console backup schemes, the disclosed interoperability gateway system and method greatly reduces the equipment needed to provide dispatch console backup, thereby decreasing equipment and operation costs, and simplifying operation by providing a solution that is virtually transparent to the dispatcher.

FIG. 2 illustrates an example embodiment wherein the disclosed interoperability gateway 200 is hosted at various dispatch centers 210 connected via an Internet Protocol (IP) network 215 to an LMR system 220 having one or more LMR sites 225. The dispatch centers 210 maintain a wired connection to the LMR system 220 through the IP network 215. Radios 235 communicate at the LMR site 225 over RF connections 240, and calls are passed to the dispatch centers 210 over the IP network 215.

Each dispatch center 210 further includes one or more dispatch consoles 230, which are connected to the local interoperability gateway 200. Dispatchers conduct call operations from the consoles 230, which include organizing calls using the TalkGroups assigned to users of the LMR system 220. Specifically, the dispatchers originate or receive calls on particular TalkGroups configured on the dispatch console 230 and via the IP network 215. The calls on the Talkgroups are placed on the LMR system 220 through an assignment of an RF channel to communicate with the LMR site 225 over RF connection 240. While the dispatchers may communicate on hundreds of TalkGroups, one call can be placed through a channel at a time, thereby limiting the number of simultaneous calls that can be placed on LMR system 220.

In the configuration illustrated in FIG. 2, the LMR system 220 is fully operational and the dispatch centers 210 are connected to the system 220 via the IP network 215. As such, the interoperability gateway 200 is inactive because it is not transmitting or processing any calls. However, although inactive, the interoperability gateway 200 may still receive calls transmitted from the system 220 through both control stations and a wired connection through the IP network 215.

Referring now to FIG. 3, when a connection failure 300 occurs between a dispatch center 210A and the LMR system 220, the interoperability gateway 200A at the disconnected dispatch center 210A detects the disconnection and becomes active to establish an RF connection 310 between the disconnected dispatch center 210A and the LMR system 220. At this point, the dispatchers operating the consoles 230A cannot access the LMR system 220 through the wired IP network connection 215. Nevertheless, the dispatchers are able to reuse the same TalkGroups present on their console 230A at the time the connection failed, to seamlessly transition to communication with the LMR system 220 through the interoperability gateway 200A. Activation of the interoperability gateway 200A is automatic, and the dispatchers continue to use their TalkGroup resources that they were using during the wired connection through IP network 215. As such, the switching from the wired connection to the wireless connection provided by the interoperability gateway 200A occurs seamlessly without dispatcher intervention or interruption.

As explained in greater detail below, any calls originated from the LMR system 220 are received by the interoperability gateway 200A via the RF connection 310, and are passed to the consoles 230A at the dispatch center 210A. Conversely, any calls that originate from the dispatch center 210A are sent via the interoperability gateway 200A over the RF connection 310 to be placed on the LMR system 220. Thus, the interoperability gateway 200A provides a virtually transparent solution, because it facilitates the continued communication with the LMR system 220 via the TalkGroups displayed on the consoles 230A with little or no interruption to the dispatcher.

It should be appreciated that, in some embodiments, the equipment comprising the interoperability gateway 200 may not be housed entirely, or in part, at the dispatch center 210, but may instead be separated and disposed at locations in the LMR system that are separate and apart from the dispatch console 210. It should also be appreciated that, in some embodiments, the interoperability gateway 200 may incorporate a distributed LMR architecture, such as that disclosed in U.S. patent application Ser. No. 14/217,150, entitled “Distributed Simulcast Architecture” and incorporated herein by reference for all purposes, wherein the interoperability gateway 200 operates as an LMR site 225 in the LMR system 220.

Operation of the disclosed interoperability gateway backup console functionality is now described with reference to FIG. 4. FIG. 4 illustrates an example embodiment wherein the interoperability gateway 400 is implemented in the backup console mode of operation to provide a connection 405 between a dispatch center 410 and an LMR system 420 (also referred to herein as the “connected LMR system”) when the dispatch center 410 loses its wired connection to the LMR system 420. In some embodiments, the interoperability gateway 400 may include a router to provide IP connectivity, one or more gateway controllers 450 to provide call control, a set of control stations 425 to provide RF connection to the LMR system 420, and one or more power supplies to provide power. In some embodiments, the interoperability gateway 400 may include additional control stations 425 and/or controllers 450 to provide redundancy in case of equipment failure.

In the example embodiment illustrated in FIG. 4, the LMR system 420 is a twelve-channel simulcast LMR system capable of supporting hundreds of TalkGroups while utilizing one control channel and up to eleven voice channels at a given moment to service radios 415 communicating with one or more LMR sites 430. Accordingly, the interoperability gateway 400 is configured to mirror the functionality of the LMR system 420 by utilizing up to twelve control stations 425, each designated to mirror one of the channels (control or voice) supported by the simulcast LMR system 420. In some embodiments, one control station 425 monitors a control channel supported by the LMR system 420, while each of the remaining control stations 425 are dedicated to one of the voice channels. For example, as shown in FIG. 4, control station 425A may be dedicated as the control channel, and each of the remaining control stations 425 are dedicated to one of the voice channels. In some embodiments, all control stations 425 may monitor the control channel, and the assignment of a control station 425 to an RF channel may be directed via the gateway controller 450.

The interoperability gateway 400 includes an interoperability site network interface (ISNI) 450 (also referred to herein as controller or gateway controller) that is connected to the control stations 425 over an IP network 440. The controller 450 controls operation of the interoperability gateway 400 by performing various functions including, but not limited to, monitoring the wired connection between the dispatch center 410 and LMR system 420, automatically activating the interoperability gateway 400 when the dispatch center 410 is disconnected from the LMR system 420, processing calls placed on and received via the control stations 425, managing connectivity of the control stations 425, and providing an interface between the interoperability gateway 400 and the consoles 435 in the dispatch center 410. In some embodiments, operation of the interoperability gateway 400 also includes deactivating the interoperability gateway 400 in the event the dispatch center 410 is reconnected with the LMR system 420 via the wired connection.

Upon failure of the wired connection between the dispatch center 410 and the LMR system 420, the controller 450 activates the interoperability gateway 400 and utilizes the control stations 425 to establish an RF connection 405 between the dispatch center 410 and the LMR system 420. When a call is originated from the LMR system 420 on a voice channel, the call is received by the corresponding control station 425, which forwards the call over the IP network 440 to the controller 450, which then passes the call to the console 435. When a call is originated from a console 435, the call is received by the controller 450, and the call is placed on the LMR system 420 using a transmit control station 425. The transmit control station 425 is a control station 425 that is assigned a voice channel and is configured to the voice channel to transmit the call to the LMR system 420. In some embodiments, the control station 425 previously assigned to the voice channel of the LMR system 420 is then reconfigured to become the transmit control station 425 to accommodate a call from the console 435 on that same voice channel.

As discussed above, the interoperability gateway 400 provides the backup console functionality by allocating a control station 425 for each channel available at the disconnected LMR system 420, rather than allocating a control station for each TalkGroup. When compared to conventional dispatch console backup schemes, which allocate control stations for each TalkGroup, the disclosed interoperability gateway system greatly reduces the equipment needed to provide dispatch console backup, thereby decreasing equipment and operation costs, and simplifying operation by providing a solution that is virtually transparent to the dispatcher.

In some embodiments, the disclosed interoperability gateway is capable of providing functionality for communicating between different LMR systems. For example, the interoperability gateway may convert a voice type or call type from one LMR system to a voice type or call type suitable for a different LMR system. FIGS. 5 and 6 illustrate example embodiments of various implementations of the disclosed interoperability gateway to provide communication between various LMR systems.

FIG. 5 illustrates an example embodiment wherein the interoperability gateway 500 is implemented to provide interoperability between a single trunking LMR site 520 and a P25 LMR system 540. The interoperability gateway 500 includes control stations 525 connected to one or more controllers 530 via an IP network 535. The single trunking LMR site 520 is an eight-channel trunking LMR system 520 capable of supporting many TalkGroups while utilizing one control channel and up to seven voice channels at a given moment to service radios 515 communicating with the trunking LMR site 520. The P25 LMR system 540 may include one or more LMR sites 545 providing communication between one or more radios 544. In the embodiment illustrated in FIG. 5, an additional controller 530 is implemented to provide redundancy.

The interoperability gateway 500 is configured to mirror the functionality of the trunking LMR site 520 by utilizing up to eight control stations 525, each designed to mirror one of the channels supported by the trunking LMR site 520. In some embodiments, one control station 525 monitors a control channel supported by the trunking LMR site 520, while each of the remaining control stations 525 are dedicated to one of the voice channels. In some embodiments, the control stations 525 may be dynamically assigned to a channel by the controller 530. Accordingly, the interoperability gateway 500 mirrors the trunking LMR site 520 by allocating a control station 525 to each of the channels supported by the trunking LMR site 520.

The interoperability gateway 500 provides interoperability between the trunking LMR site 520 and the P25 LMR system 540 by processing calls between the trunking LMR site 520 and the P25 LMR system 540. The interoperability gateway 500 establishes an RF connection 550 between the trunking LMR site 520 and the interoperability gateway 500. When a call is originated from the trunking LMR site 520 on a voice channel, the call is received by the corresponding control station 525, which forwards the call over the IP network 535 to the controller 530, which converts the call to P25 protocol and connects the call with the P25 LMR system 540. In some embodiments, the call may be sent from the controller 530 to the console 560, and then directed to the P25 LMR system 540. When a call is originated from the P25 LMR system 540, the call is received by the controller 530, and the call is placed on the trunking LMR site 520 using a transmit control station 525. The transmit control station 525 is assigned a voice channel and is configured to the voice channel to transmit the P25 call to the trunking LMR site 520. In some embodiments, the previously assigned control station 525 for the voice channel is then reconfigured to become the transmit control station 525.

FIG. 6 illustrates an example embodiment wherein one or more interoperability gateways 600 are implemented to provide interoperability between a plurality of trunking LMR sites 620 and a P25 LMR system 640, wherein the trunking LMR sites 620 are connected through a controller 610 in a multicast configuration. In the embodiment illustrated in FIG. 6, a call can be setup on a particular site 620, or it can be placed as a wide area call spanning multiple sites 620. Additionally, TalkGroups may be restricted or zoned to particular sites 620 based on system settings. For example, in the embodiment illustrated in FIG. 6, a first group 601 of sites 620 communicate using a first subset of TalkGroups, a second group 602 of sites 620 communicate using a second subset of TalkGroups, and a third group 603 of sites 620 communicate using a third subset of TalkGroups.

In the embodiment illustrated in FIG. 6, the interoperability gateways 600 connect the plurality of LMR sites 620 to the P25 LMR system 640 via IP network 650. Specifically, each interoperability gateway 600 provides interoperability between a particular group of TalkGroups via the sites 620 and the P25 LMR system 640. For example, interoperability between each of the sites 620 in the first group 601 and the P25 LMR system 640 is provided by a first interoperability gateway 600A. Similarly, interoperability between each of the sites 620 in the second group 602 and the P25 LMR system 640 is provided by a second interoperability gateway 600B, and interoperability between each of the sites 620 in the third group 603 and the P25 LMR system 640 is provided by a third interoperability gateway 600C. Each of the interoperability gateways 600 provide interoperability on the subset of TalkGroups assigned to the interoperability gateway's respective group of sites 620, and each of the interoperability gateways 600 connects via an RF link to a particular LMR site 620 within the respective gateway's group of sites 620.

In the example embodiment illustrated in FIG. 6, each gateway 600 is mapped to the channels of a particular group of sites 620. However, by restricting each gateway 600 to provide communication on a set of channels, the channel resources used for a set of TalkGroups can be reduced. Calls that are not required or intended for one group of sites 620 is not placed on the interoperability gateway 600 corresponding to the unintended group of sites 620. Thus, the channel resources for the unintended group of sites 620 are not utilized and remain available.

In the embodiment illustrated in FIG. 6, each interoperability gateway 600 is flexible and can be strategically located at multiple sites within the multicast system based on certain data such as existing fleet map and user activities. In some embodiments, a dummy LMR site may be created to serve as a gateway site to link all TalkGroups within the multicast system through an interoperability gateway 600. Because the interoperability gateway 600 is located on the dummy site, there is no need for additional RF equipment, such as an antenna system, to allow the dummy site to connect to the interoperability gateway 600. The interoperability gateway control stations can access the dummy site over an RF connection in a local environment without the need for expensive antenna, Multicoupler, and combiner equipment.

Referring now to FIG. 7, an example flow diagram 700 is provided illustrating a method in accordance with the disclosed system for providing backup connection between a dispatch center and a Land Mobile Radio (LMR) system when the dispatch center is disconnected from the LMR system. At block 701, a controller detects the disconnection between the dispatch center and the LMR system. At block 702, a communication link between the dispatch center and the disconnected LMR system is established by one or more of the control stations. At block 703, the controller allocates a first one of the control stations as a control channel for the disconnected LMR system in response to detecting the disconnection between the dispatch center and the LMR system. At block 704, the controller allocates a second one of the control stations as a voice channel for communicating with the disconnected LMR system over the voice channel.

In accordance with one or more embodiments, the disclosed interoperability gateway may support a unique set of TalkGroups (interoperability TalkGroups). Thus, a call on a TalkGroup may not be attempted through multiple LMR sites or through multiple controllers.

In some embodiments, TalkGroup IDs may be maintained across LMR systems connected by the disclosed interoperability gateway. Each interoperability TalkGroup ID on a connected LMR system may be mapped to a corresponding P25 TalkGroup ID on the P25 LMR system. This allows users to maintain their existing TalkGroup ID on the connected LMR system while creating new TalkGroups on the P25 system, thereby allowing mapping a connected LMR system TalkGroup to the same ID on the P25 TalkGroup.

Dynamic user IDs may be configured, in some embodiments, to indicate if the user is a radio user or a dispatcher. In some embodiments, when a call is placed originating from the P25 LMR system, the P25 LMR system user ID may be used even though the call may be placed through the control station. Conversely, when a call is placed originating from a connected LMR system, the user ID from the connected LMR system may be used. In some embodiments, when a console originated call is placed on the P25 LMR system, the interoperability gateway may place the call on the P25 LMR system as a console originated call to enable console preemption and parallel console functionality.

In some embodiments, the interoperability gateway may allow using a fixed user ID to place calls between a P25 LMR system and a connected LMR system. In such embodiments, when a P25 originated call is placed on the connected LMR system, the call is placed through the control station and the user ID of the control station or a dummy user ID is used. When a call is originated from the connected LMR system and placed on the P25 LMR system, a dummy P25 user ID may be used. A fixed user configuration may be useful, for example, when it is not possible to enter the P25 user IDs into the connected LMR system.

In some embodiments, each interoperability P25 TalkGroup configured in the interoperability gateway can be configured as confirmed or unconfirmed. If the TalkGroup is configured as confirmed, then, for calls originated from the connected LMR system, the interoperability gateway will wait for a successful response from all interested P25 sites before setting up the call. If the TalkGroup is configured as unconfirmed, then, for calls originated from the connected LMR system, the interoperability gateway will not wait for successful responses from all interested P25 sites before setting up the call.

In some embodiments, if the interoperability gateway receives a call originated from the connected LMR system, and identifies the corresponding TalkGroup as an unconfirmed TalkGroup, the interoperability gateway sends a proceed message to all interested P25 sites, and sends the voice stream without waiting for a call response from the interested sites. If the interoperability gateway receives a call originated from the connected LMR system, and identifies the corresponding TalkGroup as a confirmed TalkGroup, the interoperability gateway sends the call request to all interested P25 sites, and waits for a successful response from each site before setting up the call. Once a successful response is received from all interested P25 sites, the interoperability gateway sends a proceed message followed by the voice stream. In some embodiments, during the call setup period, the controller may queue up any voice data received from the connected LMR system to ensure voice integrity.

In some embodiments, a console originated call may be treated as a radio call originated from the connected LMR system. However, the user ID will indicate to the interoperability gateway that the call is originated from a dispatcher. In some embodiments, the interoperability gateway will proxy as a regular, dispatch console and setup the call on the P25 LMR system as a console originated call enabling additional features such as, for example, parallel console, console preemption, and console priority. Regarding the parallel console feature, a console originated call from a trunking LMR system will appear to the regular dispatch console users as a parallel console originated call. Regarding the console preemption feature, LMR system console originated calls will appear to the P25 LMR sites as a regular console originated call which will preempt any radio user call on the same TalkGroup on the P25 LMR system. Regarding the console priority feature, a LMR system console originated call will appear to the P25 LMR sites as a regular console originated call. As such, if the call gets queued, it will have higher priority in the queue over a radio originated call.

In some embodiments, when the interoperability gateway receives a call originated from a P25 LMR site on a confirmed TalkGroup, the interoperability gateway sends the call request to the connected LMR site through a control station. Once it receives a channel grant from the connected LMR site, the interoperability gateway sends a response to the originating P25 LMR site to complete the call setup. When the interoperability gateway receives a call originated from a P25 LMR site on an unconfirmed TalkGroup, the interoperability gateway receives the proceed message and sets up the call on the connected LMR system through a control station. Because the call is setup as unconfirmed, the P25 LMR site user may start transmitting the voice packets before the call is setup on the connected LMR system.

In some embodiments, if a P25 LMR system originated call is queued in the connected LMR system, the interoperability gateway may send a queue response to the P25 LMR site indicating the call is queued. When the call is granted in the connected LMR system, the interoperability gateway sends the successful call response to the P25 LMR system, which triggers the originating P25 LMR site to complete the call setup.

In some embodiments, if a P25 LMR system originated call is queued in the P25 LMR system, the call will already be setup in the connected LMR system while it is still queued in the P25 LMR site. When the call setup is completed in the P25 LMR system, the P25 voice data is sent to the connected LMR system.

In some embodiments, a console originated call may be setup as a radio originated call on the connected LMR system. The dispatch user ID may indicate to the connected LMR system that the call is originated by the console and, if the connected LMR system can support priority based on user ID, the console originated call may be given higher priority in the connected LMR system.

In some embodiments, the disclosed system may accommodate an emergency call, wherein the call request and voice stream from either the connected LMR system or the P25 LMR system indicates if a call is originated as an emergency call. In some embodiments, an emergency call originated on the connected LMR system will be setup as an emergency call on the P25 LMR system, and vice versa.

In some embodiments, the disclosed system may accommodate an emergency preemption, which allows a system to terminate an ongoing regular call on a TalkGroup to setup an emergency call on that TalkGroup.

In some embodiments, the disclosed system may accommodate an emergency alarm, which allows a subscriber unit to send an emergency indication over a control channel without using a voice resource. The emergency alarm is forwarded to all dispatch console positions monitoring the TalkGroup. In one embodiment, when a P25 LMR system user sends an emergency alarm, the P25 LMR site sends the emergency alarm to the interoperability gateway. If the interoperability gateway is configured for the TalkGroup, it will send the emergency alarm to the connected LMR system through a control station. The user ID of the originating P25 user may be used to send the emergency alarm. In some embodiments, the emergency alarm may be received by the Gold elite console through the connected LMR system.

In some embodiments the disclosed system may accommodate an end-to-end encryption scheme, which allows encrypted voice packets originated from the LMR system to be transmitted to the P25 system without decryption of such voice packets. The encrypted voice packets originated from the P25 system may be transmitted on the LMR system without decrypting the encrypted packets. This provides an end-to-end encryption function of LMR system.

In some embodiments an encrypted call from one system can be decrypted and re-encrypted by the interoperability gateway to provide different encryption schemes in the two systems. This allows each system to maintain its own voice security scheme while allowing end-to-end encryption.

In some embodiments, an encrypted call on one system can be decrypted by the interoperability gateway and placed on the other system as clear (non-encrypted) call. This may be useful in scenarios where encryption is required in one system and is either not required or not possible in the other system.

In some embodiments, the disclosed system may provide dynamic deployment of dispatch consoles with full access to all system TalkGroups, while the existing consoles remain active. For example, a mobile command vehicle or temporary dispatch center may be deployed in the event of large gatherings or crises.

In some embodiments, the disclosed system may provide seamless roaming by radios between P25 LMR systems without the use of direct wired connections between the LMR system infrastructures. This may be a backup or alternative to the P25 Inter Sub System Interface (IS SI) capability specified in P25 standards, which defines seamless radio roaming between P25 trunking systems.

In some embodiments, the disclosed system may provide data functionality between P25 LMR systems, users, and the dispatch equipment without the use of direct wired connections with LMR system infrastructures. This may be a backup connection for data solution or data solution between LMR system and console and related equipment deployed in a mobile command vehicle or center.

A number of additional and alternative embodiments of the disclosed system and method may be provided without departing from the spirit or scope of the present disclosure as set forth in the aspects provided herein. These various embodiments are believed to be understood by one of ordinary skill in the art in view of the present disclosure. 

What is claimed is:
 1. A gateway system for providing backup connection between a dispatch center and a Land Mobile Radio (LMR) system when the dispatch center is disconnected from the LMR system, the gateway system comprising: a controller configured to detect the disconnection between the dispatch center and the LMR system; a plurality of control stations coupled to the controller via an IP network, wherein each of the control stations are configured to establish a wireless radio frequency communication link between the dispatch center and the disconnected LMR system and; wherein the controller is further configured to, in response to detecting the disconnection, allocate a first one of the plurality of control stations as a control channel for the disconnected LMR system, and allocate a second one of the plurality of control stations as a voice channel for communicating with the disconnected LMR system over the voice channel by transmitting and receiving voice calls between the disconnected LMR system and a console of the dispatch center via the wireless radio frequency communication link; wherein the voice calls comprise radio transmissions of a plurality of service radios communicating wirelessly with the disconnected LMR system.
 2. The gateway system of claim 1, wherein each of the plurality of control stations mirror a channel supported by the disconnected LMR system.
 3. The gateway system of claim 1, wherein each of the plurality of control stations are configured to monitor the control channel of the disconnected LMR system.
 4. The gateway system of claim 1, wherein the disconnected LMR system is a trunking LMR system.
 5. The gateway system of claim 1, wherein the controller is configured to provide an interface between the gateway system and the console of the dispatch center.
 6. The gateway system of claim 1, wherein the gateway system is configured to process voice calls received from the plurality of service radios communicating wirelessly with the disconnected LMR system via the control station allocated as the voice channel.
 7. The gateway system of claim 1, wherein the gateway system is configured to process calls placed from the dispatch center to the disconnected LMR system via the control station allocated as the voice channel.
 8. A system for providing backup connection between a dispatch center and a Land Mobile Radio (LMR) system when the dispatch center is disconnected from the LMR system, the system comprising: a controller configured to detect the disconnection between the dispatch center and the LMR system; two or more control stations coupled to the controller via an IP network, wherein at least one of the two or more control stations is configured to establish a wireless radio frequency communication link between the dispatch center and the disconnected LMR system; and wherein the controller is further configured to, in response to detecting the disconnection, allocate a first one of the two or more control stations as a control channel for the disconnected LMR system, and allocate a second one of the two or more control stations as a voice channel for communicating with the disconnected LMR system over the voice channel by transmitting and receiving voice calls between the disconnected LMR system and a console of the dispatch center via the wireless radio frequency communication link, and wherein the voice calls comprise radio transmissions of a plurality of service radios communicating wirelessly with the disconnected LMR system.
 9. The system of claim 8, wherein each of the two or more control stations mirror a channel supported by the disconnected LMR system.
 10. The system of claim 8, wherein each of the two or more control stations are configured to monitor a control channel of the disconnected LMR system.
 11. The system of claim 8, wherein the disconnected LMR system is a trunking LMR system.
 12. The system of claim 8, wherein the controller is configured to provide an interface between the system and the console of the dispatch center.
 13. The system of claim 8, wherein the system is configured to process voice calls received from the plurality of service radios communicating wirelessly with the disconnected LMR system via the control station allocated as the voice channel.
 14. The system of claim 8, wherein the system is configured to process voice calls placed from the dispatch center to the disconnected LMR system via the control station allocated as the voice channel.
 15. A method for providing backup connection between a dispatch center and a Land Mobile Radio (LMR) system when the dispatch center is disconnected from the LMR system, the method comprising: detecting, via a controller, the disconnection between the dispatch center and the LMR system; establishing, via at least one of a plurality of control stations, a wireless radio frequency communication link between the dispatch center and the disconnected LMR system; and allocating, via the controller in response to detecting the disconnection, a first one of the plurality of control stations as a control channel for the disconnected LMR system, and a second one of the plurality of control stations as a voice channel for communicating with the disconnected LMR system over the voice channel by transmitting and receiving voice calls between the disconnected LMR system and a console of the dispatch center via the wireless radio frequency communication link, and wherein the voice calls comprise radio transmissions of a plurality of service radios communicating wirelessly with the disconnected LMR system.
 16. The method of claim 15, further comprising: processing voice calls received from the disconnected LMR system via the control station allocated as the voice channel; and processing voice calls placed from the dispatch center to the disconnected LMR system via the control station allocated as the voice channel.
 17. The method of claim 15, wherein each of the plurality of control stations mirror a channel supported by the disconnected LMR system.
 18. The method of claim 15, wherein each of the plurality of control stations are configured to monitor the control channel of the disconnected LMR system.
 19. The method of claim 15, wherein the disconnected LMR system is a trunking LMR system.
 20. The method of claim 15, wherein the controller is configured to provide an interface between the LMR system and the console of the dispatch center. 